(a) Field of the Invention
A fingerprint recognition sensor is provided.
(b) Description of the Related Art
A fingerprint recognition technology as a technology that determines whether a user is himself/herself by electronically reading a fingerprint of a finger of a user and comparing the read fingerprint and preinput data to verify an identity of the user is excellent in safety and convenience, low in manufacturing cost, and is applicable to various fields among bio recognition technologies.
Acquiring a high-quality image for the fingerprint is required for a reliable fingerprint recognition system having a high recognition rate and a low error rate and to this end, development of a fingerprint recognition sensor having more excellent performance is requested.
In recent years, a capacitive fingerprint recognition sensor and an optical fingerprint recognition sensor are widely used and the optical fingerprint recognition sensor is configured in a structure including a light source and an optical sensor and the optical sensor senses light emitted from the light source and reflected to sense the fingerprint of the user.
Korean Patent Registration No. 1,407,936 for the optical fingerprint recognition sensor includes an exemplary embodiment of a form to sense light reflected on the fingerprint by irradiating light from the bottom of a substrate.
However, transparency of the fingerprint recognition sensor is reduced due to a backlight unit positioned on the bottom of the substrate, and as a result, coupling with another device such as a display panel may not be easy.
Korean Patent Registration No. 1,349,924 for the optical fingerprint recognition sensor includes an exemplary embodiment that can irradiate the light from the bottom of the substrate and restrict an angle of light used for sensing the fingerprint according to a pattern of a black matrix.
However, the amount of light incident on a surface contacting the fingerprint is small due to the black matrix, and as a result, light use efficiency for the irradiated light may be low.
U.S. Pat. No. 9,245,167 for the optical fingerprint recognition sensor includes an exemplary embodiment (see FIG. 2A) of a form in which light emitted from the light source positioned on the side is reflected by a light guide and an exemplary embodiment (FIG. 5) of a form in which a minute prism structure is introduced on the bottom of the substrate to refract the light emitted from the light source toward a cover.
However, while a structure such as a reflection plate, or the like is positioned on the light guide and a structure such as a prism, or the like is positioned on the bottom of the substrate, the thickness of the fingerprint recognition sensor increases, a volume increases, and the transparency decreases, and as a result, coupling with another device such as the display panel may not be easy. Further, when the prism is used, only light having a predetermined incident angle in a narrow range is used, and as a result, the light efficiency may deteriorate and reliability of fingerprint recognition may deteriorate in media other than air. Further, manufacturing cost of the fingerprint recognition sensor may increase and a manufacturing process may be complicated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.